1. Field of the Invention
The present invention relates to a liquid discharge recording head for recording on a recording sheet by discharging liquid used for recording from an orifice (discharge port). The invention also relates to a method of manufacture therefor, as well as to a liquid discharge recording apparatus. The present invention is applicable to a copying machine, a facsimile equipment provided with communication systems, and an apparatus such as a word processor provided with a printing unit, besides a general printing apparatus.
In the specification hereof, the term xe2x80x9cprintxe2x80x9d (which may be referred to as xe2x80x9crecordxe2x80x9d in some cases) is understood to indicate not only the case where characters, graphics, or some other meaningful information is formed, but also, indicate the case where images, designs, patterns, or others are formed on a print medium irrespective of being meaningful or meaningless broadly or whether or not those are made apparent so as to be observable by human eyesight, or to indicate such a case that a medium is processed. Here, the term xe2x80x9cprint mediumxe2x80x9d means not only paper used for a printing apparatus in general, but also, means broadly cloths, plastics films, metallic plate, glass, ceramics, woods, leathers, or the like which is made capable of receiving ink. Further, the term xe2x80x9cinkxe2x80x9d (which may be referred to as xe2x80x9cliquidxe2x80x9d in some cases) should also be interpreted broadly as in the definition of xe2x80x9cprintxe2x80x9d described above, and means the liquid with which to form images, designs, patterns or the like when it is provided for a print medium or for the medium that may be used for processing a print medium or processing ink (such as to coagulate colorant or make it insoluble in ink to be used for a print medium).
2. Related Background Art
The liquid discharge recording head comprises an element substrate having a plurality of discharge energy generating elements, such as electrothermal converting devices formed thereon, and a ceiling plate having on it a plurality of fine discharge ports and a plurality of liquid flow paths communicated therewith. The liquid discharge recording head is manufactured by assembling the element substrate and the ceiling plate in the state where each of the discharge energy generating elements and each of the liquid flow paths are positioned exactly. Then, the structure is arranged so that with electric energy applied to each of discharge energy generating elements, the change of states, which is followed by abrupt voluminal changes (creation of bubbles), is caused to occur on the liquid which is supplied from the outside and in contact with each of discharge energy generating elements, thus discharging liquid by the exertion of active force on the basis of such change of states of liquid for forming images on a recording medium by the adhesion of liquid thus discharged to it.
By adoption of the recording method that uses the liquid discharge recording head thus structured, images can be recorded in high quality at high speed with a lesser amount of noises, and at the same time, the discharge ports for discharging liquid can be arranged in high density with respect to the liquid discharge recording head that records using this recording method. Therefore, it has many advantages such as to obtain recorded images in high resolution even by use of a smaller apparatus, and also, obtain color images with ease, among some others. Thus, in recent years, this recording method is widely utilized for a printer, a copying machine, a facsimile device, and many other office equipment, and further, it is utilized even for textile printing systems, and others for industrial use.
However, the conventional grooved ceiling plate is formed by resin such as polysulfone on one hand, and the element substrate is formed by silicon on the other. Therefore, even if discharge energy generating elements and the grooves of liquid flow paths are positioned exactly at the time of manufacture, there are some cases where the positions of discharge energy generating elements and the grooves of liquid flow paths are caused to deviate later due to the difference in thermal expansion ratios influenced by the temperature changes under the environments of various uses, simply because materials used for both of them are different.
In order to avoid the positional deviation between the discharge energy generating elements and the grooves of liquid flow paths owing to the different materials used for the grooved ceiling plate and the element substrate, it is conceivable to form the grooved ceiling plate and the element substrate by use of the same material. In this case, the material of grooved ceiling plate should be arranged to be identical to that of element substrate. However, it is expected that this arrangement makes the integrated formation difficult for the orifice plate and the grooved ceiling plate in some cases. In other words, the orifice plate should be made in the form of thin and long plate without any warping, which should be provided with fine discharge ports formed thereon. It is not easy to produce a plate of the kind using silicon material. Here, therefore, it is conceivable to arrange the structure in which the orifice plate is prepared separately from the grooved ceiling plate, and after the grooved ceiling plate and element substrate, both of which are formed with the same material, are bonded together, the orifice plate individually formed by the material suitable for the formation of orifice plate is bonded to the already bonded face of the grooved ceiling plate and element substrate on liquid discharging side.
Conceivably, however, the liquid discharge recording head thus structured as described above makes it extremely difficult to effectuate sealing after having positioned each of plural discharge ports formed on the orifice plate and each of liquid flow paths with respect to those liquid flow paths formed by bonding the element substrate and the grooved ceiling plate. In other words, filler should be injected as sealant between the orifice plate and the bonding face of the orifice plate having liquid flow paths formed therefor, but only around the discharge ports. For example, therefore, if sealing is not made sufficient due to a smaller amount of sealant thus filled, it is expected that liquid is allowed to leak from the bonded faces even to disable liquid discharges or, on the contrary, if filling agent is too much, a problem may be encountered that the discharge ports are clogged.
The main object of the present invention is to provide a liquid discharge recording head capable of sealing the circumference of discharge ports without clogging the discharge ports or liquid flow paths, and also to provide a method of manufacture therefor, as well as a liquid discharge recording apparatus.
The liquid discharge recording head of the present invention comprises an orifice plate having discharge ports formed therefor to discharge liquid, and the main body portion having liquid flow paths formed therein to be communicated with an opening arranged at the edge portion thereof, the discharge ports and the opening being bonded to communicate with each other. For this liquid discharge recording head, a sealing groove is arranged on the circumference of the opening along the bonded face, and filler is filled in the sealing groove. Also, the method of the present invention for manufacturing a liquid discharge recording head comprises the steps of bonding an orifice plate having discharge ports to discharge liquid formed therefor to the main body portion having liquid flow paths therein to be communicated with opening arranged on the edge portion and provided with a sealing groove on the circumference of the opening, so as to enable the discharge ports and the opening to be bonded and communicated with each other; and filling filler into the sealing groove. Further, the liquid discharge recording apparatus of the present invention comprises a liquid discharge recording head of the invention described above, and a member for mounting the liquid discharge recording head.
For such typical embodiments of the present invention, the sealing groove is formed to surround the element substrate and the grooved ceiling plate, that is, to surround the face having the opening of liquid flow paths formed therefor. The face other than the one having the sealing groove formed therefor is provided with the injecting groove for use of filling filler formed to be communicated with the sealing groove. As a result, it becomes possible to pour filler into the sealing groove from the injecting groove after the orifice plate is bonded to the face having the opening formed therefor to communicate the opening with the discharge ports of orifice plate so as to eliminate any gaps from which filler leaks between the orifice plate and the face having opening formed therefor. Thus, it is made possible to carry out sealing by distributing filler over the entire area of sealing groove in an amount required for sealing appropriately without clogging the circumference of openings or discharge ports.
Here, it may be possible to form the edge portion of injecting groove in a position on the face other than the one where the sealing groove is arranged, but not covered by the fixing margin of orifice plate which is used for fixing it to the main body portion. In this case, the edge portion of injecting groove, that is, the injecting port of injecting groove for injecting filler, is not concealed even if the fixing margin of orifice plate is fixed to the main body portion. Therefore, it becomes possible to execute the filling of filler after the fixing margin of orifice plate is fixed to the main body portion.
The face where the opening is formed may be extruded from the face of liquid supply member on the side where the sealing groove is formed. In this case, the orifice plate is pressed to the face having the opening is formed therefor, thus making it possible to prevent further any gap from being formed to allow filler to leak between the orifice plate and the face having the opening formed therefor.
The dimension of sealing groove may be the one that makes filler flowable by means of capillary force. In this case, the filler can be poured into the sealing groove without any external force exerted to enable the filler to flow after it has been injected from the injecting groove, and distribute it over the entire area in the sealing groove.
In accordance with the present invention, it becomes possible to provide a liquid discharge recording head capable of sealing the circumference of discharge ports reliably without allowing filler to clog discharge ports or liquid flow paths, and also, to provide the method of manufacture therefor, and liquid discharge recording apparatus as well.